Power Query - Variable Column and Header location from 30+ workbooks - excel

Question

I am trying to combine many workbooks with multiple sheets. The issue is on sheet 1 there is a large information header prior to the information needed to extract. As well as many merged cells that return a large number of nulls and push data into variable columns depending on the date and version of the source workbooks.
Currently sorting and promoting headers allows me to match up the first Two Columns of information needed but subsequent info is pushed right into other fields.
Is there a way to delete nulls and shift the data sets left to match fields? Or better yet identify dynamic header changes and return data to match the selected headers?
Below is an outline of the issue, unfortunately cleaning the data on the amount of sheets and workbooks isn't really an option. I'm fairly new to Power Query and can't seem to figure this one out.
c1 c2 c3 c4 c5 c6 c7
A B Null C D Null E
a b c D Null E Null
A B C Null D G E
Need A-B-C-D-E only.
= () => let
Source = Folder.Files("C:\Users\XXXXXXXX\Desktop\Log"),
#"Filtered Hidden Files1" = Table.SelectRows(Source, each [Attributes]?[Hidden]? <> true),
#"Invoke Custom Function1" = Table.AddColumn(#"Filtered Hidden Files1", "Transform File from Log", each #"Transform File from Log"([Content])),
#"Renamed Columns1" = Table.RenameColumns(#"Invoke Custom Function1", {"Name", "Source.Name"}),
#"Removed Other Columns1" = Table.SelectColumns(#"Renamed Columns1", {"Source.Name", "Transform File from Log"}),
#"Expanded Table Column1" = Table.ExpandTableColumn(#"Removed Other Columns1", "Transform File from Log", Table.ColumnNames(#"Transform File from Log"(#"Sample File"))),
#"Changed Type" = Table.TransformColumnTypes(#"Expanded Table Column1",{{"Source.Name", type text}, {"Name", type text}, {"Data", type any}, {"Item", type text}, {"Kind", type text}, {"Hidden", type logical}}),
#"Removed Other Columns" = Table.SelectColumns(#"Changed Type",{"Data", "Name", "Source.Name"}),
#"Filtered Rows" = Table.SelectRows(#"Removed Other Columns", each ([Name] = "page 1" or [Name] = "page 2" or [Name] = "page 2 +" or [Name] = "page 3 +" or [Name] = "page 4 +" or [Name] = "page 5 +" or [Name] = "page 6 +" or [Name] = "page 7 +" or [Name] = "page 8 +")),
#"Reordered Columns" = Table.ReorderColumns(#"Filtered Rows",{"Source.Name", "Name", "Data"}),
#"Expanded Data" = Table.ExpandTableColumn(#"Reordered Columns", "Data", {"Column1", "Column2", "Column3", "Column4", "Column5", "Column6", "Column7", "Column8", "Column9", "Column10", "Column11", "Column12", "Column13", "Column14", "Column15", "Column16", "Column17", "Column18", "Column19", "Column20", "Column21", "Column22", "Column23", "Column24", "Column25", "Column26", "Column27", "Column28", "Column29", "Column30", "Column31", "Column32", "Column33", "Column34", "Column35", "Column36", "Column37", "Column38", "Column39", "Column40", "Column41", "Column42", "Column43", "Column44", "Column45", "Column46", "Column47", "Column48", "Column49", "Column50", "Column51", "Column52", "Column53", "Column54", "Column55", "Column56", "Column57", "Column58", "Column59", "Column60", "Column61", "Column62", "Column63", "Column64", "Column65", "Column66", "Column67", "Column68", "Column69", "Column70", "Column71", "Column72", "Column73", "Column74", "Column75", "Column76", "Column77", "Column78", "Column79", "Column80", "Column81", "Column82", "Column83", "Column84"}, {"Data.Column1", "Data.Column2", "Data.Column3", "Data.Column4", "Data.Column5", "Data.Column6", "Data.Column7", "Data.Column8", "Data.Column9", "Data.Column10", "Data.Column11", "Data.Column12", "Data.Column13", "Data.Column14", "Data.Column15", "Data.Column16", "Data.Column17", "Data.Column18", "Data.Column19", "Data.Column20", "Data.Column21", "Data.Column22", "Data.Column23", "Data.Column24", "Data.Column25", "Data.Column26", "Data.Column27", "Data.Column28", "Data.Column29", "Data.Column30", "Data.Column31", "Data.Column32", "Data.Column33", "Data.Column34", "Data.Column35", "Data.Column36", "Data.Column37", "Data.Column38", "Data.Column39", "Data.Column40", "Data.Column41", "Data.Column42", "Data.Column43", "Data.Column44", "Data.Column45", "Data.Column46", "Data.Column47", "Data.Column48", "Data.Column49", "Data.Column50", "Data.Column51", "Data.Column52", "Data.Column53", "Data.Column54", "Data.Column55", "Data.Column56", "Data.Column57", "Data.Column58", "Data.Column59", "Data.Column60", "Data.Column61", "Data.Column62", "Data.Column63", "Data.Column64", "Data.Column65", "Data.Column66", "Data.Column67", "Data.Column68", "Data.Column69", "Data.Column70", "Data.Column71", "Data.Column72", "Data.Column73", "Data.Column74", "Data.Column75", "Data.Column76", "Data.Column77", "Data.Column78", "Data.Column79", "Data.Column80", "Data.Column81", "Data.Column82", "Data.Column83", "Data.Column84"}),
#"Filtered Rows1" = Table.SelectRows(#"Expanded Data", each ([Data.Column2] <> null and [Data.Column2] <> 16 and [Data.Column2] <> "16" and [Data.Column2] <> "LOCATION")),
#"Promoted Headers" = Table.PromoteHeaders(#"Filtered Rows1", [PromoteAllScalars=true])
in
#"Promoted Headers"
Picture

Answer 1

To get rid of nulls and slide everything to the left
add column .. index column
right click index column, unpivot other columns
right click and remove attribute column
Group on Index and add another index in each group by modifying the code to end with
each Table.AddIndexColumn(_, "Index2", 1, 1), type table}})
Expand the column using arrows atop, for the [x]values and [x] index2 fields
Click the Index2 field and transform .. pivot column, with Value as Values, advanced, do not aggregate
Sample code for transforming above BEFORE table to AFTER table
let Source = Excel.CurrentWorkbook(){[Name="Table1"]}[Content],
#"Added Index" = Table.AddIndexColumn(Source, "Index", 0, 1),
#"Unpivoted Other Columns" = Table.UnpivotOtherColumns(#"Added Index", {"Index"}, "Attribute", "Value"),
#"Removed Columns" = Table.RemoveColumns(#"Unpivoted Other Columns",{"Attribute"}),
#"Grouped Rows" = Table.Group(#"Removed Columns", {"Index"}, {{"GRP", each Table.AddIndexColumn(_, "Index2", 1, 1), type table}}),
#"Expanded GRP" = Table.ExpandTableColumn(#"Grouped Rows", "GRP", {"Value", "Index2"}, {"Value", "Index2"}),
#"Pivoted Column" = Table.Pivot(Table.TransformColumnTypes(#"Expanded GRP", {{"Index2", type text}}, "en-US"), List.Distinct(Table.TransformColumnTypes(#"Expanded GRP", {{"Index2", type text}}, "en-US")[Index2]), "Index2", "Value"),
#"Removed Columns1" = Table.RemoveColumns(#"Pivoted Column",{"Index"})
in #"Removed Columns1"